Air-conditioning system



Nov. 26, 1929. c. A. BULKELEY ET AL AIR CONDITIONING SYSTEM Filed Nov. 23, 1927 OOOOOOO 2 Sheets-Sheet 1 Patented Nov. 26, 1929 UNITED STATES PATENT OFFICE CLAUDE A. BULKELEY AND LACHLAN W. CHILD, OF BUFFALO, NEW YORK, ASSIGNORS T0 NIAGARA BLOWER COMPANY, OF BUFFALO, NEW YORK, A CORPORATION OF NEW YORK AIR-CONDITIONING SYSTEM Application filed November 23, 1927. Serial No. 235,291.

This invention relates to an apparatus for conditioning air and more particularly to an automatic control for an air conditioner which is responsive to the temperature of the room for maintaining the air in the roonr at apredetermined temperature and relative humidity.

The principal object of this lnvention 1s to provide such a control which will maintain the air in the room at the proper temperature and humidity with a minimum of refrigeration and heating of the air, thereby effecting a saving in the cost of operation of the air conditioner.

A further object is to effect this result by simple and reliable means which are not liable to get out of order with continuous use.

In the accompanying drawings:

Figure 1 is a diagrammatic representation of the air conditioning apparatus with my improved control therefor. Figure 2 is a longitudinal section through the diaphragm control motor shown diagrammatically in Fig. 1. In both views the parts are shown in a position which they occupy when the room temperature has dropped slightly below the top of range ofdesired temperature.

In an installation of air conditioning apparatus for maintaining desired conditions of the air inside a building where definite maximum dry bulb temperature and relative humidity must be maintained which are below the condition of the outside air, it is necessary to maintain the desired inside conditions by the use of refrigeration .to cool the air before blowing it into the room.

For example, an application to the textile industries is hereby given with certain conditions to be maintained by way of showing the principles involved in our scheme. It is to be understood, however, that the use of our invention is in no way restricted to air conditioning in this field, but that the same may be employed wherever and whenever its use will be to advantage or save cost of operation wherever air is to be maintained at any temperature or relative humidity.

Assume it to be required that a reeling room in a textile mill must be maintained at a temperature of egrees ahrenhe t and 70% relative humidity day and night throughout the entire year regardless of outside temperature or relative humidity. lVhen the outside air in daytime is 95 degrees there will be transmitted into the room through the roof,

in the room. To prevent the room from get ting warmer than 70 degrees, enough air in quantity and at enough lower temperature than the room must be delivered into and properly distributed in the room to absorb all this heat without rising above the desired room temperature of 70 degrees.

In employing air conditioning equipment, a large proportion (or all) of the air discharged into the room is returned to and again passed through the apparatus. The reason so large a proportion of the air is returned from the room is because the air in the room contains so much less heat or B. t. u. per cubic foot than does the outside air that it requires less refrigeration to cool it down.

In order to maintain a definite relative humidity in a room, there must be an exact amount of water vapor or moisture in the air at the required temperature of the room. In the case cited, with 70 degrees dry bulb temperature and 70% relative humidity, if this air were cooled down to approximately 60 degrees, this same air would be saturated with moisture or have 100% relative humidity, as 60 degrees is the dew point temperature. This is called the dew point because dew or moisture would be precipitated out of the air it the temperature were dropped below the 60 degrees saturated temperature. Air will hold moisture in amount depending on its temperature, the higher thetemperature, the more moisture it will hold, the converse being also true.

One of the easiest ways to maintain a given p a ure and r lat hu y n a room is first to precool all the air going to the room down to the dew point and then heat'it again, without adding any moisture to it, to the desired room temperature whereby the proper relative humidity will be maintained in the room.

In the exam le given above, all the air returned from the room, plus a small amount drawn from the outside, is all cooled down to the dew oint of 60 degrees by passing the entire voliime through a chamber filled with sprays offinely divided particles of water which is maintained at the correct temperature so that the air leaves the spray chamber saturated or at the desired dew point of 60 degrees. If this saturated air at 60 degrees temperature is discharged into the room, it must absorb a definite amount of heat per cubic foot or per ound ofweight to raise its temperature to 0 degrees or that of the room. This heat must be supplied in the room first by coming through walls and windows,

be generated by mechanical energy, fromoperators as described heretofore, or second this required amount of heat must be entirely put into the air before itenters the room, or third an amount must be put in before entering the room which added to that generated within the room will equal the ,total amount of heat required to raise the air from 60 degrees dew point to degrees, the established room temperature;

It is, therefore, evident,that a definite,

amount of air must be put into a room at or near the dew point temperature to absorb the -lmown maximum amount of heat generated in the room, or the room will not assume the cor rect dry bulb temperature and the correct relative humidity will not be obtained. If for any reason due to first. a lowering of the outside temperature as is likely to occur at night, second, a lessening of the number of operators or a decrease in the mechanical energy used in the room, or third, any resultant reduction in the amount of heat occurs due to any combination of changes in two or more of the sources of heat, that either the volume of air delivered into the room must be proportionately decreased or the air must be preheated.

If the air volume remains constant, and the air is heated between-the time it leaves the spray chamber and enters the room, the amount of refrigeration needed to keep the spray water at the same correct temperature will remain constant. If, however, the volume of air handled is reduced in proportion to the reduction in heat to be absorbed in the room, then the refrigeration required will also be reduced proportionally. While this reduction in volume of air to meet such conditions is not new, we propose a system for automatically accomplishing this reduction in amount of air delivered into the room.

Our system for accomplishing this desired proportionate reduction or increase in air volume is as follows:

Referring to Figure 1, the'letter A represents the room in which the air is to be maintained at say 70 degrees temperature and 70% relative humidity, and the letter B represents the room containing the air conditioning apparatus. The air conditioning apparatus is contained within a housing or casing 5, one end 6 of which is open to admit air from the room B into the spray chamber 7. In the spray chamber 7 are arranged a plurality of spray pipes 8 from which the refrigerated water is sprayed into the chamber in the form of a plurality of sprays or jets 9. At the inner end of the spray chamber 7 is arranged a heater 10 pastwhich the air must pass after being refrigerated in the spray chamber. This heater may be of any suitable construction and is supplied with steam or other heating medium through a steam pipe 11. The supply of steam is controlled by a diaphragm valve 12 which-may be of any suitable construction and is in turn controlled by the reduction or increase in pressure in an air pres sure control pipe 13 which connects at its other end with a thermostat 14 in the room A. From the heater 10 the air passes into a chamber 15 from which it is discharged by a fan or blower 16 into a duct 17, the outer end 18 of which opens into the room A. The thermostat 14 is supplied with air under a constant pressure of say 15 pounds through a supply pipe 19 which is connected with a suitable air compressor (not shown) or other source of air pressure.

The flow of air through the duct 17 and into the room A is controlled by dampers 20 which are pivotally mounted at their centers, and similar dampers 21 are provided in a bypass 22 and control the flow of air from the duct 17 into the room B. Both series of dampers 20 and 21 are connected by levers 23 and tie rods 24 so that as the dampers 21 move from closed toward open position, the dampers 20 move from open toward closed position, and vice versa. The movement of these dampers is controlled bya lever 25 which is pivoted intermediate its ends to an arm 26 projecting outwardly from the housing 27 of a diaphragm motor 28.

Referring to Fig. 2 this diaphragm motor 28 includes two diaphragms 29 and 30 which are spaced apart to-form a diaphragm chamber 31, these diaphragms being made of any suitableresilient material.

This diaphragm chamber is connected by a pipe 32 with the air pressure control line 13 which is connected to the thermostat 14. The motor casing 27 is supported by a base section 33. having a head 34 which is formed to provide a second diaphragm chamber 35. The outward movement of these diaphragms actuate the head 36 of a plunger 37 which is pivotally connected at its other end to the damper actuating lever 25. A spring 38 in terposed between the head 36 and a' wall 39 of the motor housing tends to hold the opcrating lever 25 in the extreme position shown by the dotted lines 0 in Fig. 2. In this position the dampers 21 are open and the dampers 20 are closed to the desired maximum extent. To prevent the dampers 21 and 20 from assuming an entirely open and'closed position respectively, an adjustable stop 40 is carried by the motor housing 27 and engages the upper end of the damper operating lever 25.

Air from the room A passes into room B to be reconditioned by the apparatus therein through an 0 ening a...

With the a ove arrangement of equipment, our system will operate as follows: Thermostat 14 throttles the air from line 19 to line 13 maintaining an 'air pressure in line 13 which varies from pounds gage. pressure to 0 gage pressure proportionately as the temperature drops in room A from say 70.5

degrees to 69.5 degrees. At the higher temperature and with 15 pounds of air in line 13 and in the diaphragm chamber 31 between the diaphragms 29 and 30 of motor 28 and the diaphragm valve 12, the dampers 21 are kept closed, the dampers are wide open and the-valve 12 is closed not allowing steam to flow into the heater 10. Thus the maximum volume of air passes from the washer and fan 16 into the room A without being raised in temperature by heater 10. The diahragm motor 28 has its diaphragm counteralanced by the spring 38 so that it begins to open the dampers 21 and close the dampers 20 as soon as the-pressure in the pressure control line 13 falls appreciably below 15 pounds and gradually continues a proportionate movement ofthese dampers as the air pressure falls in line 13 until this line pressure'has dropped to about 8 pounds under which condition the lever has come against the stop 40 and dampers 21 and 20 are at their maximum travel of open and shut position, respectively. Thus. as the room A has dropped in temperature from say 70.5 degrees to degrees due to a decrease in the heat generated in the room, asheretofore described, the volume of air delivered into the room A through duct 17 has been proportionately decreased in vol-' ,ume. During this period of reducing the volume of air delivered into the room, the balance of the air handled through the apparatus has escaped through the by-pass 22 past the dampers 21 and is again passed through the-apparatus. Only the reduced volume of air delivered into the room A returns to the apparatus through the opening 41. However, the reduced volume of air returning from room A plus the increased amount of air returning to the washer through the dampers .21 is always approximately equal to that handled through the apparatus. ,If the room A continues to fall below 70 degrees, and the air pressure in line 13 drops to 7 pounds, the diaphragm stem valve 12 begins to openat that pressure and continues to open proportlonat'elyas the room A falls in temperature to 69.5 degrees when the pressure in line 13 has dropped to approximately 0 pounds pressure, when the diaphragm valve 12 is wide open. Steam is thereby admitted to the heater and the air is warmed before being delivered by the fan into the room A.

Since the air which is allowed to pass through dampers 21 returns to the apparatus at approximately the same temperature as it left it before passing through the fan, it

of 70 degrees and must be cooled from 70.

degrees to sixt degrees, the latter being the temperature 0 the air as it leaves the spray chamber. For example, if only half the full volume of air is delivered into the room and returns to the apparatus and the other half of the full volume is returned to the apparatus without being heated, the amount of cooling done through the sprays will be reduced to practically one-half the full amount, and consequently the required amount of refrigerationiwill be reduced to about one-half the full amount. Thus a very substantial saving will be accomplished in cost of operating the apparatus.

As a further refinement and a part of our invention, we include an additional control which is constructed as follows:

Since the air discharged'through duct 17 begins to rise in temperature as the room A drops in temperature below 70 de rees and the air pressure in line 13 falls below pounds, the heater 10 as the diaphragm steam valve 12 opens will heat the air the required amount to maintain the temperature in room A near 70 degrees. As there is usually little or no source of heat in room A, other than that coming in from the outside in hot weather, and that generated in the room by operators or mechanical energy, it is evident that if the outside temperature is lower than 70 de rees,

and there are no operators and the machinery not operating (as may occur at night, particularly in spring and fall seasons and decidedly so in winter) the heater 10 may heat the air considerably above 70 degrees. In such event, the air passing through dampers 21 directly back into the apparatus will have been heated above the temperature leaving the air washer or even to a temperature above that of the room]; In such case our intended purpose of saving refrigeration would be largely defeated. Should the air be heated above room temperature, as is sure to occur when the outside air is comparatively cold, all saving in refrigeration might not only be lost, but might even be increased above the maximum requirements without further provision to avoid this. Our invention proposes a control for meeting this condition and which controlling means is preferably constructed as follows: v y

The second diaphragm chamber 35 in the diaphragm motor 28 is connected by a pipe' sure control line 13 to admit air pressure from the main pressure pipes 19 and 45 to the pipe 42 and second diaphragm chamber 35. The increase in pressure in the chamber 35is at all times proportional -to the reduction in pressure in the control line 13. 1

As the thermostat 14 with falling room temperature drops the pressure lower than 15 pounds in line 13 the relay 43 being reverse acting raises the pressure in line 42 an equal amount from zero pressure. This continues until the pressure in lines 13 and 42 are equal at about 7.5 pounds. Sinceno steam is turned into the heater 10 until the pressure in line 13 is at 7 pounds or less, the dampers 21 are open to their limit of travel and dampers 20 are in opposite position or closed to the limit of travel. As the pressure drops in line 13 to say slightly under 7 pounds the. steam valve will begin to open, and heat issupplied by heater 10 to the air entering room A. Referring to both figures, if the room A continues-to drop in temperature, the pressure in line 13 will continue to fall and through the reverse relay 43, the pressure in line 42 will rise in like amount. As soon as. the pressure from line 43 connected with the diaphragm chamber 35 is greater than in line 13 connected to the diaphragm chamber 31 between the two diaphragms, the

' relay 43, diaphragm motor 28 and diaphragm closes the dampers 21 and opens dampers 20 letting less air escape through dam ers 21 to go directly back throughthe was er. The

valve 12 are so adjusted that about the time the air is being heated to room temperature of-say about 7 0 degrees the diaphragm motor 28 Wlll havereached its limit of travel with dampers 21 entirely closed and dampers 20' entirely open, thus the full volumes of air handled is sent to the room A to maintain its temperature and since this air is as warmer warmer than the room A, it would be a disadvantage to return any of it directly to the washer through dampers 21 for the reason that it will require more cooling or refrigeration than to allow all the a1r to go-to the room A and return it to the apparatus in the regular manner. Furthermore, send ing the full volume of air to the room. A is an advantage as it tends to and will more readily keep the room up to temperature than a lesser amount.

Where along distributing duct system is required to properly distribute the air in room A, dampers 20 may be omitted as the static pressure to force the air through the duct system will be sulficient to force the desired air" through dampers 21 without the use of throttling dampers 20. With our system, the same resu ts in operating and saving of refrigeration would be obtained as if the dampers 20 were installed and operated as described.

As a whole this invention is comparatively simple considering the function which it performs, it is reliable in operation and it will operate to maintain the desired conditions of temperature and humidity and by means of the automatic control system will operate to secure such distribution of the air as to require the minimum refrigeration thereof.

We claim as our invention:

1. An apparatus of the character described including a housing having an inlet and an outlet, refrigeratin means arrangedin said housing, means for orcing the air in the room to be conditioned through' said housing, air by-pass means conducting air from said outlet to said inlet, a closure for said by-pass, and means responsive to the temperature in said room for opening and closing said bypass closure thereby to effect a regulation of the amount of refrigerated air discharged into the room.

2. An apparatus of the character described including a housing having an inlet and an outlet, air by-pass means between said outlet and said inlet, refrigerating means in said housing, means -for forcing the air in the room to be conditioned through said housing, a closure controlling the flow of air through said by-pass, a motor operating said closure, and means responsive to the temperature of said room-for controlling the move-- 'ment of said motor comprising a thermostat and means operatively connecting said thermostat and said motor.

3. An apparatus of the character described including a housing having an inlet and an outlet, by-pass means between said outlet and said, inlet, refrigerating means in said houscontrolling the 'thereb to actuate said motor inaccordance fitiit etemperature in said room.

said inlet, refri erating means-in said housing',"1 nea'ns'for forcing the air in the room to conditioned throggh said housing, "a cloow of -air through said bypass thereby to regulate the amount of ran"; discharged into said room,"a actuating said c osur'e,'a thermostat in the to be conditioned, a ressure supplyipipe for said thermostat an a pressurecontrol pressure in said pressure control pipe being varied by. the movement of saidthermostat at. apparatus of thec'haracter described including a housing having aninlet and an outlet, by-pass means between said outlet and mg, means for ibrcing the air in'the' room to be conditioned. throu h said housing,a closurecontrollingthe ow of air through said by-pass thereby to regulate the amount of I refrigerated air discharged into the roomya diaphragm motor adapted under a predetermined'air pressure to'hold said by-pass closure in-a vclosed position, a pressure control pipe connected to said diaphragm motor, a pressure supply pipe, a thermostat arranged in the room being conditioned and connected with said ipressure supply and control pipes, said there mostat-cooperating to efi'ect a reduction in the predetermined pressure in the control pipe upon a lowering of the temperature in the room below the desired temperature and thereby efiecting a corresponding opening of the by-pass closure.

5. An apparatus of the character described including a housing having an inlet and an outlet, by-pass means between said inlet and said outlet, refrigerating means in said housing, means for forcing the air in said room through said housing, a closure controlling the flow of air through said by-pass thereby to regulate the'amount of air discharged through said outlet into said room, a lever operating said closure, a diaphragm motor including a diaphragm forming a diaphragm chamber, a thermostat in the room being conditioned, a pressure control pipe communicating with said diaphragm chamber and said thermostat,

a pressure supply pipe connected to said ther- 'mostat, said thermostat cooperating to mainhousing,means forlfor'cing the air in the room to be conditioned through said housing, a clo:

sure for said outlet and a closure for said bysures whereby as one is moved toward open I PIEB POSit lOD, the other is moved toward closed 1 between said thermostat andsa1d motor, t e;-

oiitlet, air 10 .-Pass means between said outlet {and said in ct, refrigerating means in said thermostat arranged in said room and having 0 rative connection with said motor I .jwhere y upon reduction in the temperature ofsmd-room said motor is actuated to close said ioutletclosure and open said by-pass closuref. f

7 Anapparatusof the character described including a housing having an inlet and an outlet, adapted to withdraw and discharge air into the room being conditioned, refrigeratmg means arran ed in said housing adjacent the inlet end t ereof, a heater arranged in said housing between said refrigeratlng means and said outlet, a heatin medium supply p1pe for said heater, a va ve controlling the flow of the heating medium into said heater, means for forcin the air in said room through said housing, an by-pass means between said outlet and said inlet, a closure for said by-pass, a motor actuating said closure, a thermostat arranged in said. room and means operatively connecting said thermostat with said motor and said valve whereby upon variance of the room temperature from the desired temperature said closure and heating medium supply valve are actuated to provide a discharge of air in such quantity and of such temperature as to restore the air in the room to the desired condition.

8. An apparatus of the character described including a housing having an inlet and an outlet, refrigerating means arranged in said housing adjacent said inlet, a heaterarranged in said housing between said refri crating means and said outlet, a heating medium supply pipe for said heater, a valve controlling conditioned through said housing, by-pass means between said outlet and said inlet, a closure for said by-p'ass, a motor actuating sa1d closure, and means responsive to the temperature in said room for contemporaneously closing said closure and opening said heating medium supply valve.

9. An apparatus of the character described including a housing having an inlet and an outlet, refrigerating means arranged in said housing adjacent said inlet, a heater arranged in said housing between said refrigerating means and said outlet, a heating medium supply pipe for said heater, a valve controlling the flow of the heating medium into said heater, means for forcing the air in the room to be conditioned through said housing, by-

pass means' between 'said inlet and said out- I heater.

10.. An apparatus of the character described including a housing having an inlet and an outlet, refrigerating means arranged in said housing adjacent said inlet, a heater arranged in said housing between said refrigerating means and said outlet, a heating medium supply pipe for said heater, a valve controlling the flow of the heating medium into saidheater, means for forcing the air in the room to be conditioned through said housing, by-pass means between said inlet and said outlet, a closure for said by-pass, a motor operatively connected to said closure, a thermostat arranged in the room being conditioned, a pressure supply pipe connected to said thermostat, a pressure control pipe connecting said thermostat with said valve and motor and a reverse pressure relay connected with said pressure supply pipe, pressure control pipe and motor, said elements being so organized that upon a reduction in room temperature below the desired temperature a cor-' responding change of pressure'is efliected in said control pipe and during the reduction in said room temperature said motor is actuated to open said closure and upon a further reduction in the roomtemperature, said motor is actuated to close said-closure and said valve is actuated to admit the heating medium to said heater.

11. An apparatus of the character described including a housing having an inlet and an outlet, refrigerating means arranged in said housing adjacent said inlet, a heater arranged in said housing between said refrigerating means and said outlet,a heating medium supply pipe for said heater,

a valve controlling the admission of the heating medium into said heater, means for forcing the air in the room to be conditioned through said housing, air by-pass means between said outlet and said inlet, a closure for said by-pass, a lever actuating said do sure, a diaphragm motor including a casing and a pair of diaphragms forming a pair of diaphragm chambers, a spring holding the outer end of said lever against one of said diaphragms and tending to hold said closure in an open position, a thermostat arranged in said room, a pressure supply pipe for said thermostat, a pressure control pipe connecting said thermostat with one of said diaphragm chambers and with said heating mediumsuppl'y valve, said thermostat operating upon a reduction in the room tem erature below the desired temperature to e ect a corresponding reduction of pressure in said control pipe, a reverse pressure relay, a pipe connecting said reverse pressure relay with sure control pipe pressure equals the control I pipe pressure, the other diaphragm chamber is expanded to close said closure, and said heating medium supgly valve being so organized that upon re uct'ion of control pipe pressure to the point where said closure. is closed said valve is opened to admit the heating medium to said heater.

12. In an apparatus of the character described, a pressure supply pipe, a variable pressure control pipe, a reverse relay, a motor and a member actuated by said motor, said elements being operatively connected and so organized that upon a change in said control pipe pressure said motor is actuated to move said member in one direction and upon further change in said control pipe pressure said'motor is actuated to move said member in'the opposite direction.

13. In an apparatus of the character described, a pressure supply pipe, a variable pressure control pipe, a reverse relay, a motor, a member actuated by said motor, said elements bein operatively connected and so organized that upon a change in said control pipe pressure said motor is actuated to move said member in one direction and upon further change in said control pipe pressure said motor is actuated to move said member in the opposite direction, and means for adj ustably limiting the movement of said memr. I v 14. In an a paratus' of the character described, a supp y pipe having a constant pressure, a control p pe having a variable pressure, a motor including an operi sided casin and a pair of diaphragms arranged in sai casin and forming a "pair of diaphragm cham ers, a member engaging the outer diaphragm,.a reverse pressure relay, a pipe connecting said reverse pressure relay with said constant pressure supply p'ipe, a pipe connecting said reverse pressure relay with said variable pressure control pipe and a reverse pressure pipe connecting said relay with one of said diaphragm chambers, and a pipe connecting the other diaphragm chamber with said variable pressure control pipe, said reverse pressure relay being so organized that a reduction of pressure in said control pipe effects an increase in pressure in said reverse pressure pipe whereby upon an initial reduction in said control pipe pressure the outer diaphragm is drawn inwardly, thereby to effeet a corresponding movement of said memher and upon a reduction in said control pipe pressure to a point where the pressure in said reverse pressure pipe preponderates, said outer diaphragm is forced outwardly to effect a reverse movement of said member.

CLAUDE A. BULKELEY. I LACHLAN W. CHILD. 

